Slip a piece of heat shrink over the two black speed controller leads. Solder
the JST connector to one of the speed controller leads. I recommend putting the
speed controller lead in a vice or pair of pliers, then holding the soldering iron in
your dominant hand and the JST connector in the other hand. Place them together
so they are horizontally touching. Heat both wires with the iron until the tinned
leads melt together.

Now, let’s solder the speed
controllers to the motors. Tin the red
and brown leads on both speed
controllers, then tin both motor
leads. When looking at the back of
the motor, you will notice one lead
has a red dot next to it. This
indicates it is the positive lead. You
will then solder the red wire to the
positive lead on the motor. On the
second motor lead — which is not
marked — you will solder the brown
wire. Repeat this process on both
motors and speed controllers. Once
you’ve soldered the last brown lead,
you will have officially soldered
together your first combat robot!

Once all three wires are soldered together, slip the heat shrink over the solder
joint; make sure to cover all exposed wire. Use a lighter or other small flame to
compress the heat shrink around the solder joint; make sure the flame does not
touch the heat shrink. After joining the black leads together, repeat the process
and join the red wires together using the same steps you did on the three black
wires.